1. Field of the Invention
The present invention relates to a motor driving apparatus.
2. Discussion of the Background
Japanese Unexamined Patent Application Publication No. 2006-226993 discloses a motor driving apparatus to detect degradation of an insulation resistance of a motor. In the motor driving apparatus, a first point of contact is disposed between a negative line of a DC link and the ground. A second point of contact and an electric current detector are coupled to one another in series between a positive line of the DC link and one phase wire of coil coupling wires of the motor. In order to detect degradation of the insulation resistance, the first point of contact and the second point of contact are closed to form a closed circuit of a smoothing capacitor, the second point of contact, the electric current detector, the coil of the motor, the ground, the first point of contact, and the smoothing capacitor. The charging voltage of the smoothing capacitor is applied to the closed circuit. Thus, detecting the current through the closed circuit leads to detection of degradation of the insulation resistance of the motor.